The whole discussion came about as we were out walking one morning and our attention was drawn to a couple of crows on the sidewalk across the street from us. I take that back—our attention wasn’t drawn as much as it was commandeered. One crow was shouting about something rather important by the sounds of it, while the other one continued to examine (taste actually) every pebble on the sidewalk, not a metre away. I couldn’t help but comment that there was absolutely no need to shout because her (the shouty one obviously) husband (the ignoring one, also obviously) was right beside her.
And then I wondered aloud whether birds even have ears, since I had never seen a set of them on any winged specimen. (Do some of the questions that you find yourself asking out loud, sound like they come straight out of an 8-year-old?) Well, of COURSE birds have ears.
Right?
Yes, birds have middle and inner ears, and they even have an outer ear of sorts, although it doesn’t boast the elaborate dips and swirling decorations that our outer ear flaps come with. In humans, the outer ear is shaped Like That in order to funnel sounds towards the hole (aka: the ear canal). The outside rim of our ear is called the Helix and then that more inside rim is called the Antihelix.
If you’ll notice on either your own ear or that of the unsuspecting person sitting closest to you (it’s best not to get caught studying this), there is a bit of a hollow outside of the ear canal, and this hollow is called a Concha. You’ll not be surprised to know that this hollow is used to amplify sounds as they head into the ear canal. That canal is protected by a bit of cartilage sticking out from our skulls called the Tragus (it looks rather like an ear pull tab) and its partner, the Antitragus, who lives across the street and protects the canal from the ear side.
Interestingly, we have muscles set into our outer ears that could be used to move our ears were we, say, elephants or kittens. The human version of these tiny muscles are mostly just show, except for that kid in the 3rd grade who could wiggle his ears on command and has probably continued to entertain people at cocktail parties as an adult.
Our ear canals go into our heads for about an inch before ending at our ear drums, which is known to be the beginning of our middle ear.
All of the information about the middle ear and the inner ear sounds vaguely familiar from whatever was taught to us in school, and there are loads of scientific details available for anyone who wants to research our ability to hear sounds or who wonders how we are able to stand up without falling over—in case that question is next on your list.
So, birds forego the whole physical outer ear thing and skip straight to the ear canal and then on to the ear drum, etc., completely doing away with the need for a helix and antihelix and replacing the protection of our tragus and antitragus with downy feathers that keep the dust out but still let the sound in. That configuration doesn’t extend to storks or vultures who apparently just let their ear canal holes hang out for all the world to see right into. Indecent!
Also, though you probably don’t need to know this bit, birds do not produce earwax. Humans make earwax (not consciously, for the most part) as a way to move and remove ‘impurities’ in our ears. Birds don’t need that but are still able to self-ear-clean. The less we talk about earwax, the better.
The normal volume of our human day-to-day conversations is about 60 decibels, but 0 decibels is the lowest that the average hearing person can observe. We come in at 10 decibels when we breathe. Your blow-dryer hits 65 – 90 decibels. A toilet flushes at around 85 decibels. An electric drill is 95 decibels. Not surprisingly a leaf blower and a baby crying both register at the same level of approximately 110 decibels, which explains so very much. An ambulance siren rolls in around 120 decibels, depending on how far away you are from one when it’s in full scream. And a balloon popping hits 157 decibels, which does nothing to soften the visual surprise of having one suddenly explode. It’s no wonder that we have an urge to cry whenever one unexpectedly pops.
Remember when we used to go clubbing and had to yell directly into each other’s ears to make ourselves heard? Not good. It’s too late now, but not good.
Over in the world of birds, owls can hear rodents rustling under leaf litter. I can’t even hear my husband if the dishwasher is running. A crow’s caw slides in at between 60 – 85 decibels while a rooster nails 120 – 150 (?!) decibels, proving why the job of waking up the barnyard was given to him. That’s crazy loud and you’d think the rooster would drive himself half mad listening to his own time stamping, but as he opens his beak to crow, his ears automatically close so he never actually hears himself. There’s a life lesson here, if you want to delve.
The world of birds, even/especially crows, is amazingly complex and much more vibrant than we humans ever get around to acknowledging. One of the differences between us is that birds do not possess outer ears like ours (or thumbs or eyebrows or a credit history). My only reasoning for their lack of outer ear ornamentation is that if they had ears like ours stuck to the sides of their heads, it would severely impact their streamlined silhouettes during flight.
That, I have just now reasonably deduced, must be why humans can’t fly—our outer ears have ruined our aerodynamics. There’s one question that now no longer needs to be pondered! No need to thank me.
